Le connecting apparatus for subsea wellhead

ABSTRACT

The apparatus has inner and outer members nonrotatably telescoped together with a driving ring therebetween which in an extended position of the members is locked to the inner member for rotation therewith, which in a contracted position of the members is freed from the members, and which has lower teeth mating with teeth on a casing hanger whereby when the casing hanger is suspended over its landing shoulder in a subsea wellhead, in order to maintain the apparatus in the extended position, right hand rotation of the string drivingly rotates the casing despite a left hand threaded attachment between the hanger and the outer member when the casing hanger engages the landing shoulder, but when the apparatus contracts to free the drive ring, right hand rotation of the string unscrews the left hand threaded attachment to release the apparatus from the casing hanger for withdrawal of the apparatus.

United States Patent [191 Regan [451 Dec. 18, 1973 RELEASABLE CONNECTINGAPPARATUS FOR SUBSEA WELLHEAD Albert Michael Regan, Huntington Beach,Calif.

[73] Assignee: Regan Forge & Engineering Company, San Pedro, Calif.

21 Appl. No.: 160,407

[75] inventor:

[52] US. Cl. 166/0.6, 166/208 [51] Int. Cl E21b 7/12 [58] Field ofSearch l66/0.5, 208, 181, 166/177, 135

[56] References Cited UNITED STATES PATENTS 3,l36,367 6/l964 Wright etal l66/2 08 3,489,2l5 l/l970 Regan l66/208 3,587,733 ll/l968 Miller r rlee/0.5

3,350,l30 l0/l967 Ahistone et a] l66/O.5 X

Primary Examiner-Marvin A. Champion Assistant ExaminerRichard E. FavreauAtt0rney-Miketta, Glenny, Poms & Smith [57] ABSTRACT The apparatus hasinner and outer members nonrotatably telescoped together with a drivingring therebetween which in an extended position of the members is lockedto the inner member for rotation therewith, which in a contractedposition of the members is freed from the members, and which has lowerteeth mating with teeth on a casing hanger whereby when the easinghanger is suspended over its landing shoulder in a subsea wellhead, inorder to maintain the apparatus in the extended position, right handrotation of the string drivingly rotates the casing despite a left handthreaded attachment between the hanger and the outer member when thecasing hanger engages the landing shoulder, but when the apparatuscontracts to free the drive ring, right hand rotation of the stringunscrews the left hand threaded attachment to release the apparatus fromthe casing hanger for withdrawal of the apparatus.

10 Claims, 6 Drawing Figures 4 PATENIEDnEc 18 ms SHEET 1 BF 2 l I l f jJJVVE/VTOK A?- M/CA/HEL REGQA/ 55 WM, Arm-,4

IIIIIIHHHHIIIIHI & I

RELEASABLE CONNECTING APPARATUS FOR SUBSEA WELLI-IEAD BACKGROUND OF THEINVENTION This invention relates to subsea oil well tools and moreparticularly to a releasable connecting apparatus for releasableconnecting a casing hanger to a rotatable drill string for rotationtherewith and release therefrom by rotation in the same direction.

In oil wells, a casing must often be inserted into the hole after it isdrilled, and before production can be started. The purpose of such acasing is to prevent the wellhole from collapsing during production.Such a casing will be smaller in diameter than the drilled wellhole andso after the casing is inserted into the larger wellhole, the spacebetween the casing outside and the drilled hole sides is usually filledwith concrete. During the filling of this space with concrete, it isdesirable to rotate the casing in the wellhole to evenly distribute theconcrete around the casing and uniformly fill the space between thecasing and the holes. If this space is not uniformly filled, portions ofthe casing will not be supported thereby and may burst upon beingpressurized to halt the oil production of the well while expensiverepairs are made.

The above problems exist in both surface and subsea wells, but in asubsea well, the upper end of the casing is not directly accessible andany tool used to rotate the casing must also hold the casing while it isbeing lowered into the wellhole and must be releasable once the casingis positioned to permit removal of the tool from the subsea well.

BRIEF DESCRIPTION OF THE INVENTION Therefore it is the primary object ofthis invention to provide a novel releasable connecting apparatus foruse in asubsea well to releasably connect a casing or other oil welltool.

Other and additional objects of this invention are to provide such areleasable connecting apparatus which rotates and releases in the samedirection, to provide such an apparatus which is usable in a subseawell, to provide such an apparatus which rotates a casing or other oilwell tool as long as the casing is suspended thereby and which releasesthe casing when the casing is supported by other means, and to providesuch an apparatus which is inexpensive to manufacture, easy to assemble,dependable to operate and generally better than other apparatus foraccomplishing this result.

Generally, the apparatus, according to this invention, for releasablyconnecting an oil well tool to a string or the like, to rotate this toolin a well prior to landing thereof and which is locked against releaseof said tool until the tool is landed in the well, includes inner andouter tubular members mounted together in nonrotative telescopingrelationship with the inner member being connected to the string andwith the outer member being threadably connected to the oil well toolfor release therefrom upon relative rotation therebetween, and means forpreventing relative rotation between the outer member and the tool whenthe members are relatively extended and for allowing relative rotationtherebetween when said members are telescoped inwardly due to loweringof the tubing string and inner member on the landing of the tool. Themeans may be a torque transmitting means including a drive ring mountedabout the inner member and having a lower surface for .thereof,

Generally the method, according to this invention for releasing an oilwell tool from the end of a string run into a subsea well includes thesteps of connecting the oil well tool to a first portion of a couplingmember mounted to and driven by a string for release by relativerotation therebetween, locking the tool against relative rotation withsaid first portion by interlocking the tool and string by a movablesecond portion of the coupling, moving the second portion to unlock thetool and first portion by setting the tubing string down upon saidcoupling when the tool is landed in the well, and rotating the firstportion relative the landed tool to release the tool from the couplingmember.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1a and 1b together, are a sideelevational view, partially in section, of a subsea well and wellhead,with a string therein having the releasable connecting apparatusaccording to this invention, and with the casing hanger of the stringshown suspended over its landing shoulder by latch dogs extending fromthe wellhead to engage a casing running tool.

FIG. 2 is an enlarged fragmentary side cross-sectional view taken alongthe plane IIII of FIG. 1 showing the apparatus in the extended positionand the casing hanger secured thereto suspended over its landingshoulder for rotation of the casing in the wellhole.

FIG. 3 is a view similar to FIG. 2 but showing the apparatus in thecontracted position after the casing hanger has landed on its landingshoulder for rotation of the apparatus to release the casing hangertherefrom.

FIG. 4 is a fragmentary cross-sectional view taken along the plane IVIVof FIG. 2 showing the splining of the drive ring between the inner andouter members.

FIG. 5 is a fragmentary cross-sectional view taken along the plane VV ofFIG. 2 showing the splining of the inner and outer members of thereleasable connecting apparatus, according to this invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to thedrawings and particularly to FIG. 1, the releasable connecting apparatusaccording to this invention is generally denoted by the number 10. Theapparatus 10 is for use with a subsea wellhole ll drilled in the oceanfloor 12 beneath the ocean 13 from a ship or barge (not shown) at thesurface of the ocean 13, as is conventional.

The wellhole I I has located thereover a conventional wellhead 15 whichtypically includes a drilling template 16 having a central bore 17 withan upper cup shaped shoulder 18, and lateral passages 19 therethrough tothe ocean 13 which have already been filled with concrete. The drillingtemplate 16 has thereover, a guide post frame 20 with a downwardlyextending cylindrical outer casing 21 joined at the upper end to anintermediate portion 22 having an outer bowl shaped surface 23 forseating on the shoulder 18 of the template, and having an inner shoulder24 for receiving a casing hanger thereon. The intermediate portion 22 isjoined to an upper rectangular shaped portion 25. The upper portion 25has vertically extending guide posts 26 with conical guides 27therearound and with cable anchors 28 on the upper ends thereof foranchoring cables 29 from the ship (not shown) on the surface of theocean A Christmas tree unit 30 has lower guide 31 with a lower tubularprotrusion 32 and with central bore 33. The unit 30 also has a seal 34seated on the upper end of the guide 31 and with a string of blow-outpreventers 35, 36 and 37 mounted thereover and under an upper guide 38.The lower blow-out preventer has a fluid supply line 39 and a fluidreturn line 40 extending therefrom. This unit 30 is lowered from theship down the cables 27 and onto the guide post 26 to be centered by theconical guides 27 while the lower tubular protrusion 31 extends intothhe central bore of the guide post frame 20.

The upper end of the upper guide 38 has located thereover a pair oflower guide arms 41 which together with the guide 38, mount blow-outpreventer fluid control lines 42 which control the opening and closingof the blowout preventers 35, 36 and 37 from the ship on the surface ofocean 13.

A coupling 43 is provided through the lower guide arms 41 to mount theupper blow-out preventer 37 to the lower end of a hanger supporting tool44. The hanger supporting tool 44 has a two diameter central bore 45with the lower portion thereof generally the same diameter as the bore32 and the upper portion of a greater diameter to provide a landingshoulder 46 therebetween. The hanger supporting tool 44 has ahydraulically operated latch dog 47 near the upper end thereof. Theupper end of the tool 44 is joined to the lower end of riser 48 from theship (not shown). A bracket 49 is located around the riser 48 formounting the fluid lines 39 and 40 to the riser 48.

Extending down the center of the riser 48 and the wellhead apparatus 15is a rotatable string 50 including pipes 51 with right hand threads 52for connecting together. The lower end of the lowermost pipe 51 of thestring 50 is threaded into a casing running tool 53 for receiving thelatch dog 47 to temporarily axially locate the casing running tool 53 asis more fully explained in my copending US. Pat. application Ser. No.160,399, filed July 7, 1971 and entitled CASING RUNNING TOOL FOR SUBSEAWELL, filed concurrently herewith. A short length of pipe 54 is threadedinto the lower end of the casing running tool 53 and has its lower endthreaded into the apparatus 10, according to this invention.

The apparatus 10 has releasably secured thereto as will be more fullyexplained later, a casing hanger 55 having a circumferential rib 56provided a shoulder 57 for landing on the cup shaped shoulder 24 of theguide post frame 20. The casing hanger 55 also has a plurality ofgrooves 58 in the rib 56 for permitting fluid to pass between the hanger55 and the guide post frame 20. The casing hanger 55 supports adepending inner casing 59 therefrom to extend down into the wellhole 11for receiving concrete between the casing 59 and the wellhole 11 to fillthe space therebetween. In order to insure that concrete fills the spacebetween the casing 59 and the wellhole 11, it is desirable to rotate theeasing 59 while the concrete is being poured into this space. When theconcrete has set, the apparatus 10 of this invention will release thecasing hanger 55 to permit removal of the apparatus 10 and the string51, leaving the casing 59 in the wellhole 11.

Generally, the apparatus 10, according to this invention, for releasablyconnecting an oil well too] to a string 51 or the like, to rotate thetool 55 in a well 11 prior to the landing thereof, and which is lockedagainst release of the tool 55 until the tool 55 is landed in the well11, includes an inner tubular member 60 and an outer tubular membermounted together in nonrotative telescoped relation for movement betweenan extended position and a contracted position, with the inner number 60attached to the lowermost pipe 54 and the outer member 70 rotatablyreleasable attached to the tool 55, and includes means for preventingrelative rotation of the tool 55 until the tool 55 has landed and thenfor permitting relative rotation to release the tool 55, and said means85 having a drive ring between the members 60 and 70 and spline meansbetween the inner member 60 and the drive ring 90 for driving the ring90 with the inner member 60 in the extended position and for releasingthe drive ring 90 in the contracted position whereupon the outer member70 rotates relative the hanger 55. Biasing means including a spring 119between the members 60 and 70 may be provided for cushioning inwardtelescoping movement of the members 60 and 70.

Referring now to FIG. 2 wherein the apparatus 10 is shown in theextended position, and to FIG. 3 wherein the apparatus 10 is shown inthe contracted position, the inner tubular member 60 has an outsidediameter essentially equal to the outside diameter of the short pipe 54.The inner tubular member 60 has a central bore 61 having right handinternal threads 62 sized to mate with the threads of the pipe 54 forthreadably attaching the apparatus 10 into the string 50. The upper endof the member 60 has exterior vertical splines 63 extending downwardlyto end midway of the member 60 in an external, circumferential rib 64.The rib 64 has a pair of O-ring grooves 65 in the outer surface thereof,in which are located O-ring seals 66. The external surface of the member60 has an external groove 67 therein directly below the rib 64. Themember 60 is completed by provision of a circumferential external notch68 in the lower end thereof. The inner tubular member 60 is for beingtelescoped into an outer tubular member 70.

The outer tubular member 70 of the apparatus 10 is of a diameterslightly less than the central bore 33 and 45 of the wellhead 15 to passtherethrough. The member 70 has an upper circumferential external lip71, with passages 72 therethrough, for engaging the sides of bores 33and 45 as the apparatus 10 passes therethrough to centrally locate theapparatus 10. The member 70 has a central bore 73 sized to receive therib 64 of the member 60 snuggly therein and has an inwardly extendingrib 74 with inner splines 75 which as shown in FIG. 5 mate with thesplines 63 of the inner tubular member 60 for non-rotatably telescopingthe members 60 and 70 together. The lower shoulder of the rib 74 engagesthe upper shoulder of the rib 64 in the extended position as seen inFIG. 2 to prevent the members 60 and '70 from sliding apart. The outermember 70 has an inner lower notch 76 with a pair of O-ring grooves 77therein containing O-ring 78. The lower end of the inner tubular member70 has left hand internal threads 79 for threadably mating with lefthand external threads 80 on the upper end of the inner casing hanger 55for mounting the hanger 55 and the casing 59 carried thereby to theapparatus 10.

The apparatus is provided with means 85 for preventing relative rotationof the outer member 70 and the tool 55 when the members 60 and 70 are inthe extended position and for permitting relative rotation therebetweenwhen the members 60 and 70 are telescoped into the contracted position.In the preferred embodiment of this invention, the means 85 includetorque transmitting means 86 for normally engaging the tool 55 with theinner member 60 in rotative drive relation and for releasing the tool 55from said rotative drive relation upon relative axial movement of themembers 60 and 70 due to the landing of the tool 55.

In the apparatus 10, the torque transmitting means 86 includes a drivering 90 having a lower surface 91 with a plurality of downwardlyprotruding teeth 92 for mating with teeth 93 formed in the upper surfaceof the inner casing hanger 55 to non-rotatively secure the two together.The drive ring 90 also has an inner upper notch 94 providing an upwardlyfacing shoulder 95, and an outer upper notch 96 sized to mate with thelower notch 76 of the outer member 70 to locate the drive ring therein.Adjacent the upper end of the ring 90 is a circumferential upper groove97. A retainer ring 98 has a lower flange 99 which mates with the groove97 to hold the ring on the upper end of the drive ring 90. Above theretainer ring 98 are located two ring bearings 100 made of teflon orother suitable bearing material for separating the ring 90 from the rib64 of the inner member 60 when the members 60 and 70 are in thecontracted position as shown in FIG. 3.

The apparatus 10 is provided with spline means 105 between the ring 90and the inner member 60 for holding them in non-rotational relation inthe extended position of the apparatus 10 and for disengaging them inthe contracted position due to the landing of the tool 55, to permitrelative rotation between the ring 90 and the inner member 60. Thespline means 105 as best seen in FIGS. 2, 3 and 4, includes radiallyoutwardly extending splines 106 on the inner member just below thegroove 67 and radially inwardly extending mating splines 107 in thedrive ring 90 adjacent the upper end thereof. The splines 107 are ofsuch a length that when the members 60 and 70 are in the extendedposition of FIG. 2 that the splines 107 mate with splines 106 to belocked together and where the members 60 and 70 are in the contractedposition of FIG. 3, the splines 107 are spaced above the splines 106 inthe groove 67 to free the ring 90 from the members 60 and 70.

The apparatus 10 may be completed by the provision of biasing means 110for biasing the members 60 and 70 to the extended position. Theprovision of a biasing means 110 is primarily for attaching theapparatus 10 to the hanger 55 at the surface on the ship (not shown) asthe weight of the hanger 55 and casing 59, supported by the apparatus10, will bias the apparatus 10 to the extended position once theapparatus 10 is positioned in the riser 48. The biasing means 110, ofthe illustrative embodiment, includes the provision of external threads111 on the upper end of member 60 above the splines 63. An extension 112has a central bore 113 slightly larger than the pipe 52 and the outerdiameter of the inner member 60. The extension 1 12 has internal threads114 on the lower end thereof mating with the threads 111 adjacent theupper end of member 60. The

extension 1 12 has an upper outwardly extending shoulder 115 with aradial threaded hole 116 for set screw 117 to lock the extension 112 tothe short pipe 54 extending upwardly from the inner member 60. The outertubular member 70 is provided with an upper inner notch 118 to provide aspace for receiving the lower end of spring 119, the upper end of whichseats against the shoulder M5 to bias the inner and outer members and 70to the extended position of FIG. 2. The biasing of the spring 119 mustbe overcome for the members 60 and 70 to move to the contracted positionof FIG.

The apparatus 10 is assembled by sliding the bearings 100 and the drivering 90 over the lower end of the inner member 60 before the retainerring 98 is snapped around the drive ring 90 for engaging the splines 107and preventing the drive ring 91) from dropping from the inner member60. The O-rings 66 are inserted into the O-ring grooves and the outertubular member telescoped down over the inner tubular member 60 and thedrive ring 90 therearound. The spring 119 is inserted into the notch 118and the extension 112 is threaded onto the inner tubular member 60 tobias the members to the extended position and prevent the outer tubularmember 70 from sliding upwardly off the inner tubular member 60. Theassembly of the apparatus 10 is completed by the insertion of O-rings 78in O- ring grooves 77.

The assembled apparatus 10 is attached to the inner casing hanger 55 onthe ship while the casing hanger 55 is held at the upper end of theriser 48, to locate the casing 59 depending therefrom in the riser 48.The apparatus 10 has the lower end thereof placed on the upper end ofthe hanger 55 and the left hand threads 79 and threaded together untilinterference begins between the teeth 92 and 93. When the interferencebegins between the teeth 92 and 93, the inner tubular member 60 ispressed downwardly into the contracted position, permitting the innerand outer tubular members 60 and 70 to rotate relative to the hanger 55and the drive ring 90, secured thereto by the interlocking of teeth.When the outer tubular member 70 is threaded onto the casing hanger 55,the spring 119 is permitted to return the apparatus 10 to the extendedposition of FIG. 2 which locks the inner tubular member 60 to the drivering locked to the hanger 55.

The short pipe 54 has the lower end thereof threaded into the upper endof the inner tubular member 60. The set screw 117 is turned until itengages the pipe surface to lock the pipe 54 to the member 60. The upperend of the short pipe 54 has the casing running tool 53 threadedthereon. The upper end of the casing running tool 53 has threadedtherein the lowermost pipe 51 of the rotatable string 50. These toolsare now ready to be lowered into the riser 48 and into the wellhead 15to locate the inner casing 59 in the wellhole l1.

Initially, the string 50 is lowered until, as seen in FIG. 1, the groovein the casing running tool 53 is aligned with the latch dog 47. Thelatchdog 47 is extended into the groove in the tool 53 to hold thestring 50 in a first axial position. In the first axial position, theshoulder 57 of the inner casing hanger 55 is spaced a distance above thelanding shoulder 24 of the guide post frame 20, to maintain theapparatus 10 in the extended position of FIG. 2. The inner casing 59extends into the wellhole 11, ready for receiving concrete therearound.The concrete is pumped down both the supply line 39 into the centralbore of the blowout preventor 35, through the passages 72 of theapparatus 10 and through the grooves 58 in the hanger 55 to pass intothe hole 11 around the casing 59.

In order to assure a uniform filling of the space between the casing 59and the wellhole 11 with concrete, the string 51 is rotated, rotatingthe apparatus 10 in a right hand direction. Such right hand rotation ofthe apparatus 10 would unscrew the left hand threads 79 and 80 betweenthe outer tubular member 70 and the hangar 55, except that, as seen inFIG. 2, the splines 106 and 107 are interlocked to rotate the drive ring90 which is locked by teeth 92 and 93 to the hanger 55 to prevent suchrelative rotation. The rotation of the strings 51 is continued until thespace is uniformly filled with concrete, whereupon the string 50 israised slightly and the latch dogs 47 are released. The string 50 is nowlowered until the shoulder 57 of the hanger 55 seats on the shoulder 24of the guide post frame where the hanger 55 will be left to hang theinner casing 59 in the well hole 11 permanently.

To release the apparatus 10 from the hanger 55 after being landed, thestring 50 is allowed to lower until the shoulder of the running tool 53seats on the shoulder 46 of the hanger supporting tool 44 whereby theweight of the string 50 moves the apparatus 10 from the extendedposition of FIG. 2 to the contracted position of FIG. 3 against thebiasing of spring 119. This movement slides the inner member 60 relativethe outer member 70 and the drive ring 90 to move the splines 107upwardly out of meshing engagement with the splines 106 and into thegroove 67 to release the drive ring 90 from the inner member 60. Thismovement also slides the rib 64 down onto the bearing rings 100, butmaintains the driving connection between the splines 63 and 75 of theinner and outer tubular members 60 and 70. Continued right hand rotationof the string 50 rotates the inner and outer members 60 and 70 relativethe hanger 55 and the released drive ring 90 to unscrew the left handthreads 79 and 80 and separate the hanger 55 from the apparatus 10. Oncethe apparatus 10 is unscrewed, it is raised with the drill string 51 upthe riser 48, leaving the hanger 55 and the concrete surrounded innercasing 57 in the wellhole 11. The wellhole 11 is now ready to receiveproduction tools which will pump the oil therefrom.

Thus, the releasable connecting apparatus, according to this invention,is located in a pipe string for a subsea well to secure a tooltherebelow for rotation in one direction before landing and for releaseof the tool by rotation in the same direction upon landing in thewellhead.

I claim:

I. An apparatus for releasably connecting an oil well tool to a tubingstring or the like to rotate said tool in a well prior to landingthereof and which is locked against release of said tool until said toolis landed at the well, said apparatus comprising:

inner and outer tubular members mounted together in non-rotativetelescoping relation normally biased into relatively extended positionsthereof, said inner member being connected to a tubing string and saidouter member being threadably connected to an oil well tool andthreadably releasable therefrom upon relative rotation therebetween;

means for preventing said relative rotation between said outer memberand said tool when said members are relatively extended and for allowingsaid relative rotation therebetween when said members are telescopedinwardly of each other due to lowering of said tubing string and innermember on the landing of said tool and outer member so as to cause saidouter member to be threadedly released from said tool upon said relativerotation.

2. An apparatus for releasably connecting an oil well tool to a tubingstring or the like to rotate said tool in a well prior to landingthereof and which is locked against release of said tool until said toolis landed at the well, said apparatus comprising:

a first member having means thereon for connecting to tubing to besupported and rotated thereby;

a second member mounted to said first member for limited axial movementrelative thereto and to be rotated thereby and having means thereon forreleasably connecting to said tool, said last named means beingreleasable from said tool upon relative rotation therebetween;

torque transmitting means for normally engaging said tool with saidfirst member in rotative drive relation and for releasing said tool fromsaid rotative drive relation upon relative axial movement between saidfirst member and said second member due to landing of said tool.

3. The apparatus of claim 2 wherein said torque transmitting meanscomprises:

a drive ring mounted about said first member for limited axial movementthereon and having a lower surface provided with means for drivinglyengaging said tool;

spline means provided between said ring and first member for holdingthem in non-rotational relation only for a first axial position of saidring relative to said first member and being disengaged in a secondaxial position for said ring relative to said first member caused by thelanding of said tool.

4. The apparatus of claim 3 wherein:

means are provided for normally biasing said first and second membersinto a relatively extended relation by which said drive ring is biasedinto said first axial position.

5. An oil well tool coupling and running tool assembly for rotating anoil well tool in a subsea well while supporting the weight of the tubingand providing for automatic release of the coupling upon subsequentlanding of the tool, said assembly comprising:

a running tool having a landing surface and being rotatably connected toa tubing string to support the same when landed at a well;

a coupling member connected to said tubing below said running tool andreleasably coupling to an oil well tool to be rotated and landed in awell, said coupling having a landing surface thereon;

a first landing shoulder means at the subsea well for receiving saidrunning tool and supporting the same during rotation of said tubing torotate said tool in the well, said first landing shoulder means beingselectively movable to allow passage of said running tool thereby;

a second landing shoulder means at said well below said first landingshoulder for receiving and supporting said running tool when it islowered past said first landing shoulder;

a third landing shoulder means at said well below said second landingshoulder a distance less than the spacing of the landing surface on saidcoupling member below the landing surface on said running tool; and

means associated with said coupling member for allowing release of saidoil well tool from said coupling upon relative rotation therebetweenonly when said coupling is landed on said third landing shoulder.

6. An oil well tool coupling and running tool assembly as in claimwherein:

said coupling member comprises inner and outer telescoping membersnormally in protracted relation when said running tool is landed on saidfirst landing shoulder and retracted relative to. each other when saidcoupling member is landed on said third landing shoulder and saidrunning tool is landed on said second landing shoulder.

7. An oil well tool coupling and running tool assembly as in claim 6wherein said means associated with said coupling member comprises alatching means for latching said oil well tool to said tubing to berotated thereby when said coupling members are in protracted positionand releases said oil well tool from said tubing when said members arein said retracted position to allow release of said oil well tool fromsaid coupling by relative rotation therebetween.

8. An oil tool coupling comprising:

a body member with means for connecting to tubing for rotation therebyin a given direction;

a tubular member mounted to said body member for limited axial andnon-rotative movement relative thereto having means for connecting to anoil well tool which is disconnected by rotation of said tubular memberin said given direction relative to said tool; unthreaded drive ringmeans for releasably engaging said body member and said tool to rotatetogether and for disengaging from said tool on landing of said tool in awell and consequent relative axial movement between said body member andtubular member to allow release of said tubular member from said toolupon further rotation of said tubing in said given direction.

9. A casing hanger connecting tool adapted to be mounted on the end of atubing string run from a floating vessel to a remote subsea well forrotating an associated casing in the subsea well prior to landing of thecasing hanger at the well and which is automatically rendered releasablefrom said casing hanger upon such landing, said connecting toolcomprising:

a tubular body having means at an upper end thereof for mounting saidbody on a tubing string;

an outer sleeve member and means for mounting the same on said body fornon-rotative and limited axial movement relative thereto, said sleevemember having a lower end provided with means for connecting to ordisconnecting from the casing hanger upon relative rotationtherebetween;

a torque transmitting ring for engaging between said body and easinghanger to rotate said casing hanger in response to rotation of said bodyby said tubing string without turning said sleeve member relative tosaid casing hanger; and

means for mounting said torque transmitting ring on said body forlimited axial movement between a first position in which said ring islocked against relative rotation with said body and a second position inwhich said ring is free to rotate relative to said body, said ring beingmoved relative to said body into said second position by said casinghanger as said tool is lowered on landing said casing hanger in thewell, selective rotation of said tubing string thereafter causingrelease of said sleeve member and said tool from said casing hanger.

10. A method of releasing an oil well tool from the end of a tubingstring run into a subsea well comprising the steps of:

rotatively threading the oil well tool to a first portion of a couplingrotatably driven by a tubing string through a non-rotatable telescopinginterconnection therebetween;

locking said oil well tool against relative rotation with said firstportion by interlocking said tool and the tubing string by an unthreadedsecond portion of the coupling which is rotatable with respect to saidfirst portion;

axially displacing said tubing string relative to said second portion tounlock said tool and first portion by the setting of the tubing stringdown upon said coupling when said tool is landed in said well; and

rotating said tubing string and first portion relative to said landedtool to rotatively unthread and release the tool form the coupling.

1. An apparatus for releasably connecting an oil well tool to a tubingstring or the like to rotate said tool in a well prior to landingthereof and which is locked against release of said tool until said toolis landed at the well, said apparatus comprising: inner and outertubular members mounted together in non-rotative telescoping relationnormally biased into relatively extended positions thereof, said innermember being connected to a tubing string and said outer member beingthreadably connected to an oil well tool and threadably releasabletherefrom upon relative rotation therebetween; means for preventing saidrelative rotation between said outer member and said tool when saidmembers are relatively extended and for allowing said relative rotationtherebetween when said members are telescoped inwardly of each other dueto lowering of said tubing string and inner member on the landing ofsaid tool and outer member so as to cause said outer member to bethreadedly released from said tool upon said relative rotation.
 2. Anapparatus for releasably connecting an oil well tool to a tubing stringor the like to rotate said tool in a well prior to landing thereof andwhich is locked against release of said tool until said tool is landedat the well, said apparatus comprising: a first member having meansthereon for connecting to tubing to be supported and rotated thereby; asecond member mounted to said first member for limited axial movementrelative thereto and to be rotated thereby and having means thereon forreleasably connecting to said tool, said last named means beingreleasable from said tool upon relative rotation therebetween; torquetransmitting means for normally engaging said tool with said firstmember in rotative drive relation and for releasing said tool from saidrotative drive relation upon relative axial movement between said firstmember and said second member due to landing of said tool.
 3. Theapparatus of claim 2 wherein said torque transmitting means comprises: adrive ring mounted about said first member for limited axial movementthereon and having a lower surface provided with means for drivinglyengaging said tool; spline means provided between said ring and firstmember for holding them in non-rotational relation only for a firstaxial position of said ring relative to said first member and beingdisengaged in a second axial position for said ring relative to saidfirst member caused by the landing of said tool.
 4. The apparatus ofclaim 3 wherein: means are provided for normally biasing said first andsecond members into a relatively extended relation by which said drivering is biased into said first axial position.
 5. An oil well toolcoupling and running tool assembly for rotating an oil well tool in asubsea well while supporting the weight of the tubing and providing forautomatic release of the coupling upon subsequent landing of the tool,said assembly comprising: a running tool having a landing surface andbeing rotatably connected to a tubing string to support the same whenlanded at a well; a coupling member connected to saiD tubing below saidrunning tool and releasably coupling to an oil well tool to be rotatedand landed in a well, said coupling having a landing surface thereon; afirst landing shoulder means at the subsea well for receiving saidrunning tool and supporting the same during rotation of said tubing torotate said tool in the well, said first landing shoulder means beingselectively movable to allow passage of said running tool thereby; asecond landing shoulder means at said well below said first landingshoulder for receiving and supporting said running tool when it islowered past said first landing shoulder; a third landing shoulder meansat said well below said second landing shoulder a distance less than thespacing of the landing surface on said coupling member below the landingsurface on said running tool; and means associated with said couplingmember for allowing release of said oil well tool from said couplingupon relative rotation therebetween only when said coupling is landed onsaid third landing shoulder.
 6. An oil well tool coupling and runningtool assembly as in claim 5 wherein: said coupling member comprisesinner and outer telescoping members normally in protracted relation whensaid running tool is landed on said first landing shoulder and retractedrelative to each other when said coupling member is landed on said thirdlanding shoulder and said running tool is landed on said second landingshoulder.
 7. An oil well tool coupling and running tool assembly as inclaim 6 wherein said means associated with said coupling membercomprises a latching means for latching said oil well tool to saidtubing to be rotated thereby when said coupling members are inprotracted position and releases said oil well tool from said tubingwhen said members are in said retracted position to allow release ofsaid oil well tool from said coupling by relative rotation therebetween.8. An oil tool coupling comprising: a body member with means forconnecting to tubing for rotation thereby in a given direction; atubular member mounted to said body member for limited axial andnon-rotative movement relative thereto having means for connecting to anoil well tool which is disconnected by rotation of said tubular memberin said given direction relative to said tool; unthreaded drive ringmeans for releasably engaging said body member and said tool to rotatetogether and for disengaging from said tool on landing of said tool in awell and consequent relative axial movement between said body member andtubular member to allow release of said tubular member from said toolupon further rotation of said tubing in said given direction.
 9. Acasing hanger connecting tool adapted to be mounted on the end of atubing string run from a floating vessel to a remote subsea well forrotating an associated casing in the subsea well prior to landing of thecasing hanger at the well and which is automatically rendered releasablefrom said casing hanger upon such landing, said connecting toolcomprising: a tubular body having means at an upper end thereof formounting said body on a tubing string; an outer sleeve member and meansfor mounting the same on said body for non-rotative and limited axialmovement relative thereto, said sleeve member having a lower endprovided with means for connecting to or disconnecting from the casinghanger upon relative rotation therebetween; a torque transmitting ringfor engaging between said body and casing hanger to rotate said casinghanger in response to rotation of said body by said tubing stringwithout turning said sleeve member relative to said casing hanger; andmeans for mounting said torque transmitting ring on said body forlimited axial movement between a first position in which said ring islocked against relative rotation with said body and a second position inwhich said ring is free to rotate relative to said body, said ring beingmoved relative to said body into said second position by said casinghanger as said tool is lowered on landing said casing hanger in thewell, selective rotation of said tubing string thereafter causingrelease of said sleeve member and said tool from said casing hanger. 10.A method of releasing an oil well tool from the end of a tubing stringrun into a subsea well comprising the steps of: rotatively threading theoil well tool to a first portion of a coupling rotatably driven by atubing string through a non-rotatable telescoping interconnectiontherebetween; locking said oil well tool against relative rotation withsaid first portion by interlocking said tool and the tubing string by anunthreaded second portion of the coupling which is rotatable withrespect to said first portion; axially displacing said tubing stringrelative to said second portion to unlock said tool and first portion bythe setting of the tubing string down upon said coupling when said toolis landed in said well; and rotating said tubing string and firstportion relative to said landed tool to rotatively unthread and releasethe tool form the coupling.